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The present invention relates to a device and method for controlling brain tissue temperature, and in particular, to a device and method for sub-cranial temperature control of brain tissue through the use of expandable elements, such as balloons.
The benefits of the application or removal of thermal energy to or from a localized portion of a tissue area to apply or remove thermal energy is well known in the art. Balloons are commonly used to contact a tissue. It is desirable to have a delivery device that facilitates the introduction of thermal energy to a tissue region. While it is known to use balloons to contact tissue surfaces along the length of a catheter that is inserted into a vessel, a need arises for a device to apply localized thermal energy in alternate treatment scenarios. For example, as is known in the art, it is desirable to be able to apply or remove thermal energy to or from the extreme end of a catheter.
It is also desirable to avoid creating unnatural openings in a human body. However, when a medical need mandates creating an opening, making as small an opening as possible is advantageous. The need to keep openings to a minimum is particularly applicable when dealing with openings in a human skull. However, a device is needed to apply or remove thermal energy to or from a tissue area with a larger surface area than the opening through which the catheter is inserted.
Problems of uniform thermal distribution also arise with known devices. When a thermally transmissive fluid is infused into a space, the distribution of thermal energy is governed by the function of thermal convection. As such, in many situations thermal energy is not evenly distributed throughout the space. Therefore, it is desirable to provide a device which evenly distributes or removes thermal energy from tissue.
According to an aspect of the present invention, an expandable device for thermally affecting tissue is provided in which a fluid conduit having a longitudinal axis is in fluid communication with an expandable element. The expandable element has a wall defining an inner volume. The wall has a tissue contact which is non-coaxial with the longitudinal axis of the fluid conduit. The tissue contact region is operable to have a first contact surface area and a second contact surface area. The second contact surface area is larger than the first contact surface area.
According to another aspect of the present invention, another expandable element for thermally affecting tissue is provided in which a port has a longitudinal axis and is in fluid communication with an expandable element. A wall defines an inner volume and the wall has a tissue contact region. The tissue contact region is non-coaxial with the longitudinal axis of the port. The tissue contact region is operable to have a first contact surface area and a second contact surface area. The second contact surface area is larger than the first contact surface area.
According to yet another aspect of the present invention, a method of using an expandable element to affect a thermal energy change in tissue of a patent""s body is provided in which an opening is created in the patient""s body. The expandable element is in fluid communication with a fluid conduit and has a tissue contact region that is non-coaxial with a longitudinal axis of the fluid conduit. The tissue contact region is operable to have a first contact surface area and a second contact surface area which is larger than the first contact surface area. At least a portion of the expandable element is inserted into the opening, having a first contact surface area, and into a region between an outer barrier of the patent""s body and the tissue. The tissue contact region is then operated to the second contact surface area and infused with a thermally transmissive fluid, thereby affecting a thermal change in the tissue.